Endoscopic balloon cryoablation plus transurethral resection for bladder cancer: A phase 2, multicenter, randomized, controlled trial.

Abstract

Cryotherapy is a prevalent percutaneous ablative therapy for solid tumors. Here, we report a novel device using liquid nitrogen for endoscopic cryotherapy of bladder cancer. In this multicenter, randomized, parallel controlled, Phase 2 trial, we compared endoscopic balloon cryoablation (EBCA) with a single instillation (SI) of pirarubicin after transurethral resection (TUR). Eligible participants were randomly assigned (1:1) to the TUR-EBCA or TUR-SI group. Repeat TUR or tissue biopsies were performed to evaluate residual tumor at 4 to 6 weeks after primary treatment. The primary end point was the local control rate. The secondary end points included the tumor upgrading/upstaging, catheter indwelling duration, and adverse events. In total, 205 patients received EBCA or SI after TUR between November 2017 and September 2020, of whom 163 completed all the required interventions. In the per-protocol set, the local control rate was 91.5% (75/82) in TUR-EBCA group compared with 76.5% (61/81) in TUR-SI group (risk difference, 15%; 95% CI, 0.03-0.27, p < .001), meeting the criteria for noninferiority. Similar results were found in the modified intention-to-treat analysis. Tumor upgrading/upstaging was found in five patients from the TUR-SI group. There was no significant difference in the catheter indwelling duration (5.1 vs. 5.2 days, p = .76) or serious adverse event rate (3.0% vs. 3.9%, p = .52). The median follow-up time of post hoc analysis was 31 (range, 15-50) months. Patients in the TUR-EBCA group had a better recurrence-free survival and progression-free survival. EBCA is a safe and effective adjuvant therapy with TUR for non-muscle-invasive bladder cancer. This is the first randomized trial that evaluated endoscopic cryotherapy after transurethral resection (TUR) of bladder tumors. The efficacy and safety analysis shows endoscopic balloon cryoablation (EBCA) is a promising alternative. Results report that EBCA is not inferior to a single instillation of intravesical chemotherapy in eliminating residual bladder tumor. Further analysis with ∼3 years' median follow-up suggested a better prognosis in patients who received EBCA after TUR.